It seems Lightning came in contact with some radioactive waste which had ...effects on both his physical characteristics and a bit of size growth.

Unfortunately the radioactivity caused a second mind to be created overriding my own creating foxzilla, and he is having a bit of rage fit in his new body, I'm just kinda watching from the inside as he destroys the city. So I apologize if he steps on your house.... or you as I have no control. His hide is impervious to all weapons so my advice is to run!

Fantastic artwork made by :iconlord-kiyo: posted with his permission